Yes, you're correct. When you start your iMac in macOS Recovery, you should see a window with four options, including Disk Utility at the bottom.
The error message “The recovery server could not be contacted” generally indicates that your iMac cannot communicate with Apple's recovery servers. This can happen because of an Internet connection problem, an incorrect system date and time, or an issue with the older macOS High Sierra recovery installer ... which also may indicate that this iMac is much older than 6 or 7 years old.
Before attempting anything else, let's identify your iMac and check a couple of things.
- Identify your iMac: Look on the underside of the iMac's stand for its serial number. You can enter that number at checkcoverage.apple.com to see whether Apple identifies the model. Please let us know the model and year, if available. Don't post your serial number here.
- Check your Internet connection: While in macOS Recovery, look for the Wi-Fi symbol in the upper-right corner of the screen. Make sure your iMac is connected to your Wi-Fi network. If possible, connecting directly to your router using an Ethernet cable would be preferable.
- Check the system date: From the menu bar at the top of the Recovery screen, select Utilities > Terminal. Enter the following command and press Return: date
- This will display the date and time currently set on your iMac. Please let us know what it reports.
For now, there's no need to erase the disk again or attempt another installation. Once we know your iMac model and have confirmed its Internet connection and system date, we can determine the most appropriate way to reinstall macOS.
However, please be aware that, most likely, this Mac will be considered "Obsolete" by Apple Support and may not be worth the effort to get it up and running.
